Tankless Water Heater- good idea?

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Mr.T

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Checking in with the brain trust here on GD.com on going with a tankless water heater. We are building a new house so I’ve been thinking about everything that goes into it.
Water heater will be electric whether we go traditional or tankless. My thought is to go tankless with a hot water recirculating pump.
Is going tankless a good idea?
Is a tankless with a recirculating pump a good idea?
 
Best thing i did to my house. Instant forever hot water. I got the rennai industrial unit. Had it about 10 years now. Love it. Unit was 1500$ then; convert to 3/4 gas line and run power to it. My wife will take 30 minute showers, we all take showers in the morning (5 people basically a shower on from 4:45-6 am) with the washing machine going too; water never gets cold
 
I believe they need yearly cleaning. Installation with the correct valving make it an easier process but when I looked into them, they start to plug up in hard water situations without yearly flushing. I may have read that electric systems are much more expensive to run than a natural gas system. Been awhile since I dug into the info. I had decided I would stick with a gas unit though.
 
Fireballsocal said:
I believe they need yearly cleaning. Installation with the correct valving make it an easier process but when I looked into them, they start to plug up in hard water situations without yearly flushing. I may have read that electric systems are much more expensive to run than a natural gas system. Been awhile since I dug into the info. I had decided I would stick with a gas unit though.
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I’ll look into the cleaning issue, thanks.
I wish natural gas was an option, but LP is the only option in the neighborhood right now, hence planning on going electric.
 
Sausage450r said:
Best thing i did to my house. Instant forever hot water. I got the rennai industrial unit. Had it about 10 years now. Love it. Unit was 1500$ then; convert to 3/4 gas line and run power to it. My wife will take 30 minute showers, we all take showers in the morning (5 people basically a shower on from 4:45-6 am) with the washing machine going too; water never gets cold
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Did you install the recirculating system also?
 
Fireballsocal said:
I believe they need yearly cleaning. Installation with the correct valving make it an easier process but when I looked into them, they start to plug up in hard water situations without yearly flushing. I may have read that electric systems are much more expensive to run than a natural gas system. Been awhile since I dug into the info. I had decided I would stick with a gas unit though.
Click to expand...
10 years here with yearly cleaning (flush with vinegar) never had an issue and we have extremely hard water and i’ve definitely missed a year or two here and there. I went with a gas unit (propane) you will still need a 110 outlet for the igniter and Mine has a digital control unit i mounted in the laundry roomIMG_8101.jpegunit and the recirculation setup
IMG_8103.jpegIMG_8102.jpeg
 
Sausage450r said:
10 years here with yearly cleaning (flush with vinegar) never had an issue and we have extremely hard water and i’ve definitely missed a year or two here and there. I went with a gas unit (propane) you will still need a 110 outlet for the igniter and Mine has a digital control unit i mounted in the laundry roomunit and the recirculation setup
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Exactly. I think the bypass valving may now be code. I found some people online who had a hard piped system with no bypass so they needed to disconnect the system every time to flush. They also could have installed it themselves. A bucket with vinegar and a sump pump with hose seemed to be the hot ticket to flush the system.
 
Electric tankless for a typical family of 4 will need a huge breaker and wiring.
 
Have a tankless (Fountain Valley), no issues. No recirc' pump. Takes a bit to get hot water at the back of the house - where the 2 bathrooms are. Sinks are worse than the shower. Wish I had a pump!

Have a recirc' pump but on a traditional water heater (Prescott) and love it.
 
Fireballsocal said:
Exactly. I think the bypass valving may now be code. I found some people online who had a hard piped system with no bypass so they needed to disconnect the system every time to flush. They also could have installed it themselves. A bucket with vinegar and a sump pump with hose seemed to be the hot ticket to flush the system.
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Exactly how i do it. Have 3 neighbors we all installed the water heaters together and share the flush kit
 
we have two gas water heaters one on both ends of the house. im on LP we have a circulation pump on both for instant hot water but we also have a timer 5,10,30, 1 hour 2 hour, 4 hour on the wall wired in. we love it. i wake up and hit the 10 min button. turn my shower on in 1 to 2 min later with instant hot water, sinks etc in 10 min circulation pump turns off until the next use. when my daughter takes her showers she hits the 30 min button
 
Sausage450r said:
10 years here with yearly cleaning (flush with vinegar) never had an issue and we have extremely hard water and i’ve definitely missed a year or two here and there. I went with a gas unit (propane) you will still need a 110 outlet for the igniter and Mine has a digital control unit i mounted in the laundry roomView attachment 130794unit and the recirculation setup
View attachment 130795View attachment 130796
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Let's talk about those Speed Queens though:). They've been on Amys radar for years- worth the money?
 
Instant water heaters and a recirculating pump is a bad idea. You will be circulating hot water unnecessarily. If you have a long distance between, say your laundry, kitchen and bathrooms you are better off installing smaller units. I know in commercial situations we have hooked them up in both men's and women's bathrooms as well as in the breakroom and all of them were pretty close to each other.
Recirculating pumps are better used in a traditional water heater set up. where if you return the water that is in the line as it cools off back into a 80-gallon tank it doesn't take much to heat it back to max temp but with an instantaneous one there is not any stored water to absorb the cooler water.
 
wash11 said:
Let's talk about those Speed Queens though:). They've been on Amys radar for years- worth the money?
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Hell ya. I have 3 kids they run non stop. Got tired of constantly having to fix the home depot garbage. I asked the lady at appliance parts in el cajon if there was a washer/dryer that never breaks? She didnt hesitate and said speed queen. They only make industrial grade so they arent super fancy. They arent very cheap either at 1750$/each. Had them about 4 years now zero issues. 100% american made
 
I have had nothing but issues with mine for awhile (Rheem). I installed it myself. Kept throwing a slue of codes during the winter months. I am on LP and I have it plumbed with approx 6ft of 3/4" line off of the 1 1/4" main (no recirc pump). What I have learned is that they are just sensitive when its cold and set up to use LP. Make sure your vent pipes are plumbed per the instructions. Make sure that your fixtures flow adjustments are set correctly as well (My house was a new home I built, so new fixtures weren't adjusted yet). Make sure your regulator on your LP tank is set to the right PSI. Do your annual cleanings (vinegar/water). I use a 5gal bucket and a transfer pump from Harbor Freight. Make sure that your heater is scheduled to be off when your family is typically taking showers/baths. Make sure the condensate line is plumbed to a drain. Make sure you do not let your LP tank get too low on LP (we get refilled at 30-40% on our 200gal tank).

I have finally got it pretty dialed in after 4 years of having it. Shower or tub takes about 2mins or less to get hot (complete other side of the house). It will occasionally throw a code but its typically when its cold/windy, the dryer, washer and heater are all running at the same time and the wife turns the tub faucet on at full blast. So now its something we just have to be mindful of. Which who wants to do that right?? lol

Me being who I am... whenever we stay at an AirBNB I check out their water heater set ups lol. I have stayed at a couple of homes with my same exact water heater but set up on NG. They work flawlessly.... even with all things running and no recirc pump. So I might just have a sensitive one for some weird reason... Just my experience to help you make your decision. I will say, Rheem has some pretty good customer support. They have walked me through tons of troubleshooting.
 
MWB said:
Instant water heaters and a recirculating pump is a bad idea. You will be circulating hot water unnecessarily. If you have a long distance between, say your laundry, kitchen and bathrooms you are better off installing smaller units. I know in commercial situations we have hooked them up in both men's and women's bathrooms as well as in the breakroom and all of them were pretty close to each other.
Recirculating pumps are better used in a traditional water heater set up. where if you return the water that is in the line as it cools off back into a 80-gallon tank it doesn't take much to heat it back to max temp but with an instantaneous one there is not any stored water to absorb the cooler water.
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And what's the sparky think of a 38kw (Rheem's sizing recommendation for a 1.5 bath + kitchen) electric tankless on a residential panel...? :D
 
If you live in a cold environment DON'T go tankless. If you live in San Diego.........Go Tankless! Peace
 
nzulmer said:
I have had nothing but issues with mine for awhile (Rheem). I installed it myself. Kept throwing a slue of codes during the winter months. I am on LP and I have it plumbed with approx 6ft of 3/4" line off of the 1 1/4" main (no recirc pump). What I have learned is that they are just sensitive when its cold and set up to use LP. Make sure your vent pipes are plumbed per the instructions. Make sure that your fixtures flow adjustments are set correctly as well (My house was a new home I built, so new fixtures weren't adjusted yet). Make sure your regulator on your LP tank is set to the right PSI. Do your annual cleanings (vinegar/water). I use a 5gal bucket and a transfer pump from Harbor Freight. Make sure that your heater is scheduled to be off when your family is typically taking showers/baths. Make sure the condensate line is plumbed to a drain. Make sure you do not let your LP tank get too low on LP (we get refilled at 30-40% on our 200gal tank).

I have finally got it pretty dialed in after 4 years of having it. Shower or tub takes about 2mins or less to get hot (complete other side of the house). It will occasionally throw a code but its typically when its cold/windy, the dryer, washer and heater are all running at the same time and the wife turns the tub faucet on at full blast. So now its something we just have to be mindful of. Which who wants to do that right?? lol

Me being who I am... whenever we stay at an AirBNB I check out their water heater set ups lol. I have stayed at a couple of homes with my same exact water heater but set up on NG. They work flawlessly.... even with all things running and no recirc pump. So I might just have a sensitive one for some weird reason... Just my experience to help you make your decision. I will say, Rheem has some pretty good customer support. They have walked me through tons of troubleshooting.
Click to expand...
Sounds to me like your tank regulator is going bad. Take a look at your flame on your stove (if gas) when its operating well. then when you are having issues. I bet it will be lean. Extremely common for them to get lean in the cold when failing. Fwiw i have diff brand and its an outdoor unit so its self venting (no ducting), i live in the mountains and we average 20s/30s (nov-april) and get a few days well into teens and even single digits. My gas company wont fill my tank until it hits at least 15%. Never had any of these issues. But i’ve had 2 regulators fail in 12 years symptoms are always lean flame in cold weather
 
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